Activated Glycerol Carbonates, Versatile Reagents with Aliphatic Amines: Formation and Reactivity of Glycidyl Carbamates and Trialkylamines

Abstract

International audienceno abstrac

Solvent-Free Glycidyl Carbamate Oligomerization and Solvent Affinity of Oligomers

“…This proton is deshielded from 3.5 to 4.9 ppm, which can be attributed to the close proximity of the carbamate moiety (Scheme , proton k ). This observation is in agreement with our previous work where it has been shown that this type of proton is indeed at around 5 ppm . The lower integration of this signal indicates that this transfer reaction is in minority, corresponding roughly between one-fourth and one-third of the oligomerization process.…”

“…From previous results within the group, the synthesis of N , N- glycidyl carbamates 1 (Scheme ) is a three-step process starting from glycerol carbonate 2 , a renewable molecule. − It involves the activation of the primary alcohol as a sulfonate using tosyl chloride to form the tosylated glycerol carbonate 3 . This cyclic carbonate then reacts with a primary or a secondary amine, leading to the formation of the carbamate function.…”

“…Synthesis of glycidyl N,N-carbamates was achieved using previously reported protocols from our group. 21 Glycidyl carbamates are purified by flash chromatography. Prior to use, they are dried for 2 h over CaH2 under a vacuum and then distilled twice under CaH 2 using a Büchi Glass Oven Kugelrorh.…”

“…4-Dimethylaminopyridine (DMAP) (Acros Organics, 99%), 4-pyrrolidinopyridine (PPY) (Acros Organics, 98%), 9-azajulolidine (AJ) (Aldrich, 97%), calcium hydride (CaH 2 ) (Acros Organics, 93%, 10–100 mm and Alfa Aesar, 92%, coarse powder), sodium iodide (NaI) (Acros Organics, 99%), and dithranol (Sigma, 97%) were used as received. Synthesis of glycidyl N , N -carbamates was achieved using previously reported protocols from our group …”

“…This observation is in agreement with our previous work where it has been shown that this type of proton is indeed at around 5 ppm. 21 The lower integration of this signal indicates that this transfer reaction is in minority, corresponding roughly between one-fourth and one-third of the oligomerization process. Whether this reaction principally happens intramolecularly or inter-molecularly is still uncertain, but we suggest a mechanism to obtain such intramolecular migration through a five-membered ring (Scheme 6).…”